This invention relates generally to golf clubs and to methods for making them and, more particularly, to golf clubs and related methods in which the club head incorporates an added weight component to provide the head with a desired weight.
One important parameter of golf clubs is the weight of their heads. The weight of the head must be carefully controlled, not only to meet the particular needs of the individual golfer using the club, but also to combine with the golfer's other clubs to form a matched set. Golf club manufacturers, therefore, customarily weigh each club head during the manufacturing process and add one or more components of precise weight so as to adjust the club head's weight to a desired overall value.
The added components for adjusting the club head's weight have taken many different forms. One common form, which has been used with metal wood-type golf club heads, is a material such as epoxy that is added in selected amounts to the club head's hollow cavity. Although this use of epoxy has been generally effective in correcting for weight variances in golf club heads, negative side effects can result. For example, the epoxy can affix to the inner surface of the club head's ball-striking face, which can have adverse effects, such as lowering the face's coefficient of restitution. Also, pooling of the epoxy can displace the club's center of gravity, and can affect the club head's sound at ball impact, in an indeterminate way.
Another common form for the added weight component has been a metalic plug installed within the axial bore formed by the hollow shaft of the club, where it joins to the club head's hosel. Such shaft weight plugs also have been formed of alternative materials such as metallic powder dispersed within a compressible binder and housed within a sheath. Although generally effective in providing the club head with the desired weight, such shaft weight plugs sometimes can loosen and cause undesired rattling during the club's use. Also, if the need ever arises to replace the club's shaft, the shaft weight plug will necessarily be removed with the old shaft and an equivalent weight might not be installed in its place when the new shaft is attached to the club head.
It should therefore be appreciated that there is a need for an improved golf club head, and method for making it, in which the head's weight can be tailored to a precisely selected value, without adversely affecting important parameters such as the club head's coefficient of restitution or center of gravity, and without being susceptible to loosening during use or removal when the club's shaft is replaced. The present invention fulfills this need and provides further related advantages.